Power lines are widely used in many settings to carry 50 Hz or 60 Hz alternating current to power the worldwide economy. They form an important part of the power distribution system, carrying power from generation facilities all the way to the locations where it is used. The power distribution system may include many types of power lines with high voltage lines used closer to the power generation facilities and lower voltage lines closer to the locations where the power is used, such as homes and businesses, for example. Medium voltage lines, carrying voltages on the order of 30,000 Volts, are used in between.
A power company may desire to obtain accurate measurements of power-related parameters of the power lines in order to manage and maintain the power lines. Such measurements include one or more voltage measurements. For example, voltage measurements may be combined with current measurements to determine, and then manage, the amount of reactive power throughout the power distribution system (e.g., by using the measured voltage and current to determine how to operate switched capacitor banks and/or other components of a power distribution system). As another example, voltage measurements may be used to detect power theft. Voltage measurements may also be used for other purposes. For example, voltage measurements may be used to detect faults in the power distribution system, or to monitor and/or minimize the voltage at the end customers for Conservative Voltage Reduction (CVR) purposes of saving energy.
Conventional approaches to measuring the voltage of a high voltage power line involve using metal (e.g., copper) wire(s) or potential transformers (PT) to electrically couple a voltage sensor to a voltage carrying (i.e., “hot”) wire of the power line and a neutral wire of the power line in order to measure the voltage between the voltage-carrying wire and the neutral wire.